Songbirds in decline?

Reports have local experts concerned about several species

Several area songbird species have experienced declines in recent years, according to authorities. Some of them just migrate through southeastern Minnesota while others have nested here for millennia.
“The grassland birds have been slowly declining in numbers for years,” retired schoolteacher Gary Erickson said last week.
Erickson, who taught in Chatfield, St. Charles, and Kingsland, has also authored two books; “Nature: A Beginner’s Guide,” and “The Geology of Bluff Country: featuring Fillmore County.”
“As our farms have turned from dairy to more corn/soybeans, we have lost our hay fields, set aside acres, and even some pastures (a downside of ethanol that no one likes to talk about).” he noted via email. “The Meadowlarks and Bobolinks are way down, but that is an ongoing result of habitat loss. We have fewer Tree Swallows and Blue Birds at our place this year, but both of these species more than likely took a hit from the late-cold spring...
Erickson also said that large flocks of Grackles and Redwing Blackbirds are not as common as they once were. Even though the latter don’t flock in the summer, those who take notice when the birds are gathered together can see a difference.
“I have written about this loss of grassland species several time(s) in the last few years (in the Nature Notes articles)-in particular to the Meadowlarks,” he continued. “Because big ticket items like deer and Bald Eagles are doing well many people are under the illusion that wildlife in general is doing well. That simply is not the case for most songbirds, butterflies, and small less noticed creatures in our ecosystem.
Just one example is the Rusty Blackbird. These are only seen passing through southern Minnesota, since they nest to the north, and winter in southern states. But Erickson calls their decline “worrisome,” and others agree.
Birding columnist Al Batt cited a report from the Cornell Lab of Ornithology that states: “The Rusty Blackbird has undergone one of the sharpest and most mystifying recent declines of any North American songbird. The North American Breeding Bird Survey estimates that populations declined by 6.2 percent every year between 1966 and 2010 — a cumulative decline of 94 percent...
“It’s not clear what has caused the population declines,” he noted, “but loss of wet woodland habitat through drainage, clear-cutting, and conversion to agriculture is a possibility — particularly in the southeastern U.S. where some 80 percent of the population winters.
“The historically severe hunting of beavers across North America may also have reduced habitat for Rusty Blackbirds by reducing the number of beaver ponds; the resurgence of beaver populations may be restoring some of this habitat. Rusty Blackbirds from northeastern North America have been recorded with unusually high mercury contamination and could be contributing to their decline in this region.”
As far as locally breeding songbirds, evidence of serious declines is uneven, according to Jamie Edwards. She serves as a nongame wildlife specialist with the Minnesota Department of Natural Resources (Rochester).
“I have had numerous reports of fewer birds this year from different locations,” Edwards reported. “I have checked with a few different bird experts and none seem to have any evidence that there is a documented reduction in birds. It seems spotty. In some areas, bird numbers seem lower than normal and other areas, they seem fine or increased. We have not had any die-offs for most species and know of none in their wintering grounds that might explain localized shortages.
“With late springs for the last two years, we did see spring deaths in early returning birds such as phoebes and bluebirds. People would find a pile of dead birds in their bluebird boxes. This has also been a bad year for gnats and biting flies, which cause nest failure for several species. We have had issues with bluebirds again due to the insects and also with loons where nests are abandoned or young die.
“The cooler than normal springs were also hard on migrating warblers which are dependent on insects. I recall last year seeing many more warblers on the ground or low in trees and appearing weak due to the lack of insects. I didn’t see that as much this year, but the late spring I am sure was hard on warblers trying to move back north.
“With the increased mosquitoes this year, we have not yet experienced a West Nile (virus) outbreak in birds. It is possible that this disease can affect birds, but we have not seen any evidence of this yet this year. “Lastly, with the harsh winter, we also experienced birds grouping up more, rather than spreading out to various feeders. What can happen with this is that birds will get accustomed to going to a group of feeders and stay in that area, rather than moving out, which might explain the higher bird numbers in some areas.
But with reports of fewer birds in certain areas, Edwards said that it’s important for bird enthusiasts to volunteer their time for bird surveys. A couple of examples are the Christmas bird count and the backyard feeder count, she noted.
“When we don’t have data to compare numbers from year to year, it makes it very subjective to determine if there is something going on,” she concluded. “Since it is often hard to find dead songbirds, we don’t see the evidence and don’t have specimens to test for various diseases. If you have any interest in participating in different bird surveys, a good place to get into this is the Cornell website. www.birds.cornell.edu Under the Citizen Science tab, there are various surveys you can participate in and ways to report sightings of birds.